While English does not typically use capital initial letters for emphasis as a grammatical point, some folks do it as a stylistic choice. German does it for all nouns, and so sometimes this stylistic choice in English gives a feeling of old and mysterious history, back when the two languages were closer. See Winnie the Pooh and The Hobbit for some examples. As in this case, it lends air to the phrase as being a culturally significant well-understood phenomenon. There are things are simply Not Talked About in polite family life, such as why auntie has lived with another lady for the past 30 years.